Vertical Step‐Growth Polymerization Driven by Electrochemical Stimuli from an Electrode

Abstract We present herein the vertical step‐growth polymerization of a monomer A‐B through individual A–A or B–B coupling driven by electrochemical switching of positive and negative bias on a self‐assembled A or B electrode. The monomer Ru II (bda)AB (bda=2,2′‐bipyridine‐6,6′‐dicarboxylate), in which A and B are pyridine moieties with pendant carbazolyl and vinyl groups, could be dimerized at oxidative (ca. 1.0 V vs. Ag/Ag + ) or reductive potential (ca. −1.8 V) to give a self‐assembled Ru II (bda)PA or Ru II (bda)PB monolayer (P=pyridine with a pendant phosphonic acid) on ITO glass. This polymerization enabled the sequence‐ and topology‐controlled synthesis of surface‐confined molecular wires with single‐molecule precision on an electrode. The electrocatalytic performance of the vertically orientated molecular wires for water oxidation increased with increasing molecular length and exceeded that of both the self‐assembled monolayer and a randomly electropolymerized film, which have previously been studied as typical models.